Getting Switch Management BIA

[barry.ard]

Some background:

For a management application I need to retrieve the mac-address that a switch uses when tagging the remote-id field of dhcp requests when dhcp snooping is enabled. Specifically, when dhcp nooping is enabled, the remote-id field in a dhcp packet contains a mac-address of the switch on which the dhcp'ing client is attached.

I would like to know what the mac-address is that will be specified and if that is available in a MIB. On our C4500 it will be the first mac-address specified by doing:

sh module 1

but that is not availabe on our C3500 switches.

I can get the mac-address+1 by looking at the BIA of the first available interface:

sh int gi1/1

This is great by I need to find a MIB that makes this available.

On our C3[56]00 switches the mac-address can be determined by looking at ENTITY-MIB::entLogicalContextEngineID

but that doesn't give anything meaningful on the C4500.

Thanks,

Barry

[Joe Clarke · Accepted solution]

What about ifPhysAddress for the first interface in each switch? That is, get the ifIndex for the first interface (i.e. Gi1/1 on the 35[56]0 and the interface which matches pattern '.*Ethernet1/[0-9]+' on the 4500), then do an SNMP Get on ifPhysAddress.INDEX.

[barry.ard]

I swear I have been looking at this all day and didn't notice that!! Looks good.

Thanks jclarke,

Barry.